Electrical devices such as electrical connectors typically have an electrical cable or conductor extending from the device. It is necessary to securely fasten the electrical conductor to the electrical device to prevent the conductor from being pulled free from the device which can damage the conductor and the electrical device. In addition, pulling or tearing the electrical conductor from the electrical device can render the device inoperable and can seriously injure the operator due to the electrical current carried in the conductor. Electrical connectors and other electrical devices typically include an assembly for clamping or otherwise securing the end of the electrical conductor to the device. Electrical devices and in particular electrical connectors are primarily constructed for use with a normal range of standard size cable. However, there are instances where cables smaller than the standard size are desired or required. Thus, it is important to have an electrical connector or other device that accommodates different size electrical conductors. Many of the electrical devices currently available are not able to effectively accommodate different size electrical conductors.
Examples of such assemblies for securing a standard size electrical conductor in a connector or other electrical device are disclosed in U.S. Pat. Nos. 2,490,153 to O'donnell, 2,911,616 to Townsend and U.S. Pat. No. 3,402,382 to De Tar. These devices generally include a relatively large diameter polymeric threaded screw extending through an outer wall of the housing of the device to press the electrical conductor against the opposite side of the housing. This arrangement has the disadvantage of being limited in the extent of the translational movement of the screw and thus limited in size of the electrical conductor which can be secured. These devices are not always able to effectively grip electrical conductors of different sizes because of the lower mechanical advantage of converting rotary motion to linear clamping thrust of a large diameter screw. Furthermore, the head of the screw cannot include teeth that engage the conductor, since the rotational movement of the screw needed to apply the clamping force will damage the conductor.
Another common construction of electrical devices include a fixed clamping jaw and a movable clamping which are biased toward each other by screws or other means to grip the electrical conductor. Examples of this type of electrical device are shown in U.S. Pat. Nos. 5,046,961 to Hoffman; 3,784,961 to Gartland Jr.; U.S. Pat. No. 3,605,059 to Lipinski; and U.S. Pat. No. 3,856,376 to Poliak et al. Of these prior devices, only U.S. Pat. No. 3,784,961 to Gartland is specifically directed to a clamp assembly able to accommodate cables of different diameter. The clamp assembly disclosed in this patent includes a recess in the fixed jaw and a recess in the movable jaw to accommodate large size cables. An insert can be inserted into the recess of the fixed jaw to reduce the dimension of the passage between the jaws so as to effectively grip the cable. Although this structure utilizing the insert effectively grips cables of different diameters, it is necessary to remove the movable jaw from the assembly to conveniently remove the insert, thereby requiring an additional step for the operator. In addition, the removal of the insert inevitably results in the insert being lost and thus precluding the subsequent clamping of a smaller cable. Since the insert may fit loosely in the clamping jaw, it also tends to become separated from the clamping jaw during shipping. Since all inserts are for the less frequently used small diameter cords, they must always be removed before clamping a standard size cable. Finally, failure to remove the insert, which is sized for the smallest cord range, when clamping a standard size cable may result in damage to the cable or the connector.
The above-noted devices demonstrate a continuing need in the art for an electrical device that is able to accommodate different size electrical conductors. There is further a need for electrical devices where the assembly for accommodating different size cables is captively retained with the main body of the device to prevent loss of components.